This disclosure relates to the field of wireless telecommunications and more particularly to a sleeve enclosure for extending the functional capability of a cell phone. Publication WO 2020/098540 discloses a double molding process wherein in a first molding step, an antenna is embedded within a resin jacket and in a second molding step the resin jacket is embedded within a device case by an insertion molding processes. Publication JP2006/148751 discloses the coupling of antennas built into a cover which when placed over the case of a portable terminal are positioned in close proximity to internal antennas of the terminal and are thereby able to be inductively coupled for strengthening transmitted signals.